Bond pad configurations for controlling semiconductor chip package interactions

ABSTRACT

A semiconductor chip includes at least one integrated circuit device and a bond pad that is electrically connected to the at least one integrated circuit device. The bond pad has an irregular configuration when viewed from above that corresponds to a first area portion that is defined by a first substantially regular geometric shape when viewed from above and a second area portion adjacent to the first area portion. The second area portion is located at a greater distance from a centerline of the semiconductor chip than any part of the first area portion when viewed from above, and two sides of the first area portion are substantially aligned with and substantially flush with two respective sides of the second area portion.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional of co-pending application Ser. No. 13/218,555,filed Aug. 26, 2011.

BACKGROUND

1. Field of the Disclosure

Generally, the present disclosure relates to sophisticated semiconductordevices, and, more particularly, to bond pad configurations forcontrolling interactions between semiconductor chips and carriersubstrates during the chip/carrier joining process.

2. Description of the Related Art

In the manufacture of modern integrated circuits, it is usuallynecessary to provide electrical connections between the varioussemiconductor chips making up a microelectronic device. Depending on thetype of chip and the overall device design requirements, theseelectrical connections may be accomplished in a variety of ways, suchas, for example, by wirebonding, tape automated bonding (TAB), flip-chipbonding, and the like. In recent years, the use of flip-chip technology,wherein semiconductor chips are attached to carrier substrates, or toother chips, by means of solder balls formed from so-called solderbumps, has become an important aspect of the semiconductor processingindustry. In flip-chip technology, solder balls are formed on a contactlayer of at least one of the chips that is to be connected, such as, forexample, on a dielectric passivation layer formed above the lastmetallization layer of a semiconductor chip comprising a plurality ofintegrated circuits. Similarly, adequately sized and appropriatelylocated bond pads are formed on another chip, such as, for example, acarrier package, each of which corresponds to a respective solder ballformed on the semiconductor chip. The two units, i.e., the semiconductorchip and carrier substrate, are then electrically connected by“flipping” the semiconductor chip and bringing the solder balls intophysical contact with the bond pads, and performing a “reflow” processso that each solder ball bonds to a corresponding bond pad. Typically,hundreds of solder bumps may be distributed over the entire chip area,thereby providing, for example, the I/O capability required for modernsemiconductor chips that usually include complex circuitry, such asmicroprocessors, storage circuits, three-dimensional (3D) chips, and thelike, and/or a plurality of integrated circuits forming a completecomplex circuit system.

In many processing applications, a semiconductor chip is bonded to acarrier substrate during a high temperature so-called ControlledCollapse Chip Connection (C4) solder bump reflow process. Typically, thesubstrate material is an organic laminate, which has a coefficient ofthermal expansion (CTE) that may be on the order of 4-5 times greaterthan that of the semiconductor chip, which, in many cases, is made upprimarily of silicon and silicon-based materials. Accordingly, due tothe coefficient of thermal expansion mismatch between the chip and thesubstrate (i.e., silicon vs. organic laminate), the substrate will growmore than the chip when exposed to the reflow temperature, and as aconsequence, stresses will be imposed on the chip/substrate package asthe package cools and the solder bumps solidify. FIGS. 1 a-1 c, whichschematically illustrate at least some of the possible effects that mayoccur on a chip package during this process, will now be described.

FIG. 1 a schematically illustrates a chip package 100, which includes acarrier substrate 101 and a semiconductor chip 102. The semiconductorchip 102 typically comprises a plurality of solder bumps 103, which areformed above a metallization system 104 (see FIG. 1 c) of the chip 102.During the chip packaging assembly process, the semiconductor chip 102is inverted, or “flipped,” and brought into contact the carriersubstrate 101, after which the chip package 100 of FIG. 1 a is exposedto a solder bump reflow process 120 at a reflow temperature that exceedsthe melting temperature of the solder bump material. Depending on thespecific solder alloy used to form the solder bumps 103, the reflowtemperature may be upwards of 200-265° C. During the reflow process 120,when the material of the solder bumps 103 is in a liquid phase, both thecarrier substrate 101 and the semiconductor chip 102 are able tothermally “grow” in a substantially unrestrained manner, based on therespective coefficient of thermal expansion of each component. As such,both the carrier substrate 101 and the semiconductor chip 102 remain inan essentially flat, non-deformed condition, although each will grow bya different amount due to their different coefficients of thermalexpansion.

FIG. 1 b, on the other hand, schematically illustrates the chip package100 during a cool-down phase, when a thermal interaction begins to takeplace between the carrier substrate 101 and the semiconductor chip 102.As the chip package 100 cools, the solder bumps 103 solidify andmechanically join the package substrate 101 to the semiconductor chip102. As the chip package 100 continues to cool after solder bump 103solidification, the CTE mismatch between the materials of the carriersubstrate 101 and the semiconductor chip 102 cause the substrate 101 toshrink at a greater rate than the chip 102. Typically, this differencein thermal expansion/contraction is accommodated by a combination ofout-of-plane deformation of both the carrier substrate 101 and thesemiconductor chip 102, and some amount of shear deformation of thesolder bumps 103. Other localized effects may occur in the semiconductorchip 102 in areas immediately surrounding the solder bumps 103, asillustrated in FIG. 1 c and described below.

FIG. 1 c schematically illustrates an area of the semiconductor chip 102surrounding an individual solder bump 103A after cool-down of the chippackage 100. For simplicity, the semiconductor chip 102 has beeninverted compared to the chip packaging configurations illustrated inFIGS. 1 a-1 b, and the carrier substrate is not shown. Furthermore, onlythe uppermost metallization layers 104A, 104B and 104C of ametallization system 104 of the semiconductor chip 102 are shown in FIG.1 c, any metallization layers below layer 104C, device layers, orsubstrate layers of the chip 102 have not been depicted. Thesemiconductor chip 102 also includes a bond pad 105 formed in the lastmetallization layer 104A, a passivation layer 106 formed above the lastmetallization layer 104A, and a solder bump 103A formed above the bondpad 105. Additionally, as shown in FIG. 1 c, the bond pad 105 is incontact with a contact structure 107 so as to facilitate the electricalconnection of the solder bump 103A and the carrier substrate 101 (notshown in FIG. 1 c) to an integrated circuit (not shown) of thesemiconductor chip 102 formed in the device level (not shown) below themetallization system 104. For illustrative purposes only, the contactstructure 107 may include, for example, a contact via 107B formed in themetallization layer 104B, a conductive line 107C and a contact via 107Din the metallization layer 104C, and the like, whereas otherconfigurations may also be used.

During the cool-down phase, the out-of-plane deformation of the chippackage 100 that is caused by the thermal interaction of thesemiconductor chip 102 and the carrier substrate 101 will develop as ashear load 103S, a tensile load 103T, and bending moment 103M across thesolder bump 103A. However, since the solder material is, in general,very robust, and typically has a strength that exceeds that of thematerials that make up the semiconductor chip 102—and in particular, themetallization system 104—relatively little deformation energy will beabsorbed by the solder bump 103A. Instead, the majority of the loads103S, 103T and 103M will be translated through the bond pad 105 and intothe metallization layers underlying the solder bump 103A, resulting inhighly localized tensile stresses, such as a vertical or uplift tensilestress 104U, and a lateral or stretching tensile stress 104S. If thesetensile stresses are high enough, a local delamination of one or more ofthe uppermost metallization layers may occur below the solder bump 103A.Typically, a metallization layer delamination will manifest as a crack108, and will normally occur where the uplift tension is highest—i.e.,near the edge 105E of the bond pad 105, as shown in FIG. 1 c. In manycases, the crack 108 may only occur in a single metallization layer,such as the layer 104B shown in FIG. 1 c, whereas in other cases, thecrack 108 may propagate deeper into the underlying metallization system104, from one metallization layer to another.

Delamination failures and cracks, such as the crack 108, that may occurin a metallization layer below a solder bump 103 are sometimes subjectto premature failure, as the solder bump 103 may not make a goodelectrical connection to the contact structures below. However, sincethe delamination/crack defects described above do not occur until thechip packaging assembly stage of semiconductor chip manufacture, thedefects will generally not be detected until a final quality inspectionis performed. Typically, after the flip-chip operation is completed, thechip package 100 will be subjected to acoustic testing, such as C-modeacoustic microscopy (CSAM). Cracks 108 that may be present in themetallization system 104 of the semiconductor chip 102 below the solderbumps 103 will have a white appearance during the CSAM inspectionprocess, and are therefore sometimes referred to as “white bumps,”“white spots,” or “ghost bumps.” White bump defects impose a costlydownside to the overall chip manufacturing process, as they do notoccur, and hence cannot be detected, until a significant material andmanufacturing investment in the chip has already occurred.

Moreover, recent changes and advances in the types of materials used insophisticated semiconductor devices have also had an impact on thefrequency in which white bumps occur. For example, for many years, thematerials used for forming solder balls used in flip-chip technologyincluded any one of a variety of so-called tin/lead (Sn/Pb) solders.Typically, the alloys that were used for most Sn/Pb solders have a levelof ductility that enabled the Sn/Pb solder bumps to deform under theloads induced during the cool-down phase of the solder bump reflowprocess, thereby absorbing some of the out-of-plane deformation energydiscussed above. However, in recent years, industries have generallymoved away from the use of Sn/Pb solders in most commercialapplications, including semiconductor processing. Accordingly, lead-freesoldering materials, such as Sn/Ag (tin-silver), Sn/Cu (tin-copper),Sn/Ag/Cu (tin-silver-copper, or SAC) solders, and the like, have beendeveloped as substitute alloys for forming solder bumps on semiconductorchips. These lead-free substitute soldering materials generally have ahigher material strength and lower ductility than most of thecommonly-used Sn/Pb solders, and also typically require highertemperatures for reflow. As such, less deformation energy is absorbed bylead-free solder bumps, and a commensurately higher loading is impartedon the metallization system underlying the solder bumps, whichsubsequently increases the frequency of white bump occurrence.

Additionally, the development and use of dielectric materials having adielectric constant (or k-value) of approximately 3.0 or lower—which areoften referred to as “low-k dielectric materials”—has led to anincreased incidence of white bumps. Typically, low-k dielectricmaterials have lower mechanical strength, mechanical modulus, andadhesion strength than do some of the more commonly used dielectricmaterials having higher k-values, such as silicon dioxide, siliconnitride, silicon oxynitride, and the like. As metallization systemsutilize more metallization layers that are made up of low-k dielectricmaterials, there is a greater likelihood that the lower strength low-kmaterials will rupture when exposed to the loads that are imposed on themetallization layers underlying the solder bumps, thus leading todelaminations and cracks—i.e., white bump defects. In particular, crackstend to occur, or at least initiate, in the low-k metallization layersthat are closest to the upper surface of the a semiconductor chip—i.e.,closest to the last metallization layer—as the deformation energy isgreatest near the upper surface, and lessens in lower metallizationlevels. Furthermore, it appears that the type of white bump problemsdescribed above are even further exacerbated in metallization layerscomprised of ultra-low-k (ULK) materials having k-values ofapproximately 2.7 or lower.

It should be noted that, while FIGS. 1 a-1 c describe typical white bumpproblems that may be associated with flip-chip packaging problems, theissues identified above are equally applicable to other chip packageconfigurations, such as 3D-chips and the like. Accordingly, and in viewof the foregoing, there is a need to implement new design strategies toaddress the manufacturing issues associated with white bumps that occurduring typical chip packaging operations. The present disclosure relatesto process device designs and methods that are directed to avoiding, orat least mitigating, the effects of one or more of the problemsidentified above.

SUMMARY OF THE DISCLOSURE

The following presents a simplified summary of the present disclosure inorder to provide a basic understanding of some aspects disclosed herein.This summary is not an exhaustive overview of the disclosure, nor is itintended to identify key or critical elements of the subject matterdisclosed here. Its sole purpose is to present some concepts in asimplified form as a prelude to the more detailed description that isdiscussed later.

Generally, the subject matter disclosed herein relates to sophisticatedsemiconductor chips that may be less susceptible to the occurrence ofwhite bumps during semiconductor chip packaging operations, such asflip-chip or 3D-chip assembly, and the like. One illustrativesemiconductor chip disclosed herein includes at least one integratedcircuit device and a bond pad that is electrically connected to the atleast one integrated circuit device. Furthermore, the bond pad has anirregular configuration when viewed from above that corresponds to afirst area portion that is defined by a first substantially regulargeometric shape when viewed from above and a second area portionadjacent to the first area portion. Additionally, the second areaportion is located at a greater distance from a centerline of thesemiconductor chip than any part of the first area portion when viewedfrom above, and two sides of the first area portion are substantiallyaligned with and substantially flush with two respective sides of thesecond area portion.

Also disclosed herein is an exemplary semiconductor chip that includesat least one integrated circuit device and a bond pad that iselectrically connected to the at least one integrated circuit device.The bond pad has a substantially irregularly shaped overall bond padconfiguration when viewed from above that includes, among other things,a first bond pad area portion that is defined by a first substantiallyregular geometric shape when viewed from above and a second bond padarea portion that is defined by at least part of a second substantiallyregular geometric shape when viewed from above. Furthermore, an uppersurface of the second bond pad area portion is substantially coplanarwith an upper surface of the first bond pad area portion and two sidesof the first bond pad area portion are substantially aligned with andsubstantially flush with two respective sides of the second bond padarea portion.

In yet another illustrative embodiment of the present disclosure, asemiconductor chip includes a first integrated circuit device, a secondintegrated circuit device, a first bond pad that is electricallyconnected to the first integrated circuit device, and a second bond padthat is electrically connected to the second integrated circuit device.The first bond pad has a substantially irregularly shaped overall bondpad configuration when viewed from above that includes, among otherthings, a first bond pad area portion that is defined by a firstsubstantially regular geometric shape when viewed from above, whereinthe first bond pad area portion has a first area centroid that islocated at a first distance from a center of the semiconductor chip. Thefirst bond bad further includes a second bond pad area portion that isdefined by at least part of a second substantially regular geometricshape when viewed from above, wherein the second bond pad area portionhas a second area centroid that is located at a second distance from thecenter of the semiconductor chip that is greater that the firstdistance. The second bond pad has a substantially regularly shapedoverall bond pad configuration when viewed from above that is defined bya third substantially regular geometric shape that is substantially thesame as the first substantially regular geometric shape. Moreover, thethird substantially regular geometric shape has a third area centroidthat is located a third distance from the center of the semiconductorchip that is less than the first distance.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIGS. 1 a-1 b schematically illustrate a flip-chip packaging operationof a semiconductor chip and a carrier substrate;

FIG. 1 c schematically illustrates out-of-plane loading on a solder balland metallization system of a semiconductor chip after the flip-chippackaging operation of FIGS. 1 a-1 b;

FIG. 2 a schematically illustrates a plan view of a semiconductor chipin accordance with one illustrative embodiment of the presentdisclosure;

FIGS. 2 b-2 c schematically illustrate plan views of representativeprior art bond pads;

FIGS. 2 d-2 f schematically illustrate plan views of a bond pad inaccordance with one illustrative embodiment of the present disclosure;

FIGS. 2 g-2 m schematically illustrate plan view of bond pads inaccordance with further illustrative embodiments of the presentdisclosure;

FIG. 3 a schematically illustrates plan and section views of arepresentative prior art bond pad;

FIGS. 3 b-3 f schematically illustrate plan and section views of bondpads in accordance with additional illustrative embodiments of thepresent disclosure; and

FIGS. 3 g-3 h schematically illustrate plan and section views of bondpads in accordance with yet further illustrative embodiments of thepresent disclosure.

While the subject matter disclosed herein is susceptible to variousmodifications and alternative forms, specific embodiments thereof havebeen shown by way of example in the drawings and are herein described indetail. It should be understood, however, that the description herein ofspecific embodiments is not intended to limit the invention to theparticular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Various illustrative embodiments of the present subject matter aredescribed below. In the interest of clarity, not all features of anactual implementation are described in this specification. It will ofcourse be appreciated that in the development of any such actualembodiment, numerous implementation-specific decisions must be made toachieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which will vary fromone implementation to another. Moreover, it will be appreciated thatsuch a development effort might be complex and time-consuming, but wouldnevertheless be a routine undertaking for those of ordinary skill in theart having the benefit of this disclosure.

The present subject matter will now be described with reference to theattached figures. Various structures and devices are schematicallydepicted in the drawings for purposes of explanation only and so as tonot obscure the present disclosure with details that are well known tothose skilled in the art. Nevertheless, the attached drawings areincluded to describe and explain illustrative examples of the presentdisclosure. The words and phrases used herein should be understood andinterpreted to have a meaning consistent with the understanding of thosewords and phrases by those skilled in the relevant art. No specialdefinition of a term or phrase, i.e., a definition that is differentfrom the ordinary and customary meaning as understood by those skilledin the art, is intended to be implied by consistent usage of the term orphrase herein. To the extent that a term or phrase is intended to have aspecial meaning, i.e., a meaning other than that understood by skilledartisans, such a special definition will be expressly set forth in thespecification in a definitional manner that directly and unequivocallyprovides the special definition for the term or phrase.

In general, the presently disclosed subject matter is directed tosemiconductor chips wherein at least some of the bond pads formed in theupper metallization layer of the chip metallization system haveconfigurations that are adapted to reduce, or at least mitigate, theoccurrence of white bumps caused by the differential thermal expansioneffects imposed on the metallization layers of the semiconductor chipduring chip packaging operations. In particular, bond pads that arelocated in areas of a semiconductor chip that are typically exposed tothe highest out-of-plane loads caused by the CTE (coefficient of thermalexpansion) mismatch between the semiconductor chip and the carriersubstrate may have irregular or composite configurations that areadapted to reduce the magnitude of the crack-inducing stresses and/orstrains induced in the metallization layers underlying a given solderbump and bond pad. For example, since the size of a body—i.e., itslength or width—is one factor that may have a significant effect on thetotal amount of thermal expansion that body undergoes when exposed to anelevated temperature, the points of greatest thermal interaction mayoccur in those areas of the semiconductor chip which are farthest from aneutral center, or centerline, of the chip. Accordingly, at least someof the bond pads having irregular or composite configurations may belocated in one or more of the corner regions of the semiconductor chip,where the differential thermal expansion problems discussed above may bethe greatest. Moreover, these stress and/or strain mitigation effectsmay be of particular importance when the affected metallization layersbelow the bond pads are made up of low-k and/or ultra-low-k (ULK)dielectric materials, both of which generally have substantially reducedmechanical strength as compared to typical oxide or nitride dielectrics.

It should be understood that, unless otherwise specifically indicated,any relative positional or directional terms that may be used in thedescriptions below—such as “upper,” “lower,” “on,” “adjacent to,”“above,” “below,” “over,” “under,” “top,” “bottom,” “vertical,”“horizontal,” and the like—should be construed in light of that term'snormal and everyday meaning relative to the depiction of the componentsor elements in the referenced figures. For example, referring to theschematic cross-section of the semiconductor chip 102 depicted in FIG. 1c, it should be understood that the passivation layer 106 is formed“above” the last metallization layer 104A, and the conductive bond pad105 is positioned “below” or “under” the solder bump 103A. Similarly, itshould also be noted that the passivation layer 106 may be positioned“on” the last metallization layer 104A in those embodiments wherein noother layers or structures are interposed therebetween.

FIG. 2 a schematically depicts a plan view of an illustrative embodimentof a semiconductor chip 200 in accordance with one illustrativeembodiment of the present disclosure. The semiconductor chip 200 mayhave a substantially rectangular configuration, with a chip length 201and a chip width 202, as well as a chip center 203 through which runs afirst centerline 203X aligned with the chip length 201 and a secondcenterline 203Y aligned with the chip width 202. Depending on thespecific application, the chip length and width dimensions 201, 202 ofthe semiconductor chip 200 may range from approximately 0.5 cm up toapproximately 2.5 cm or even larger, and they may have the same (i.e., asquare chip) or different (i.e., a rectangular chip) dimensions. Incertain illustrative embodiments, the semiconductor chip 200 may includea plurality bond pads 204 that have a substantially regularly shapedsurface area, and a plurality of bond pads 205 that have a substantiallyirregularly shaped surface area. Additionally, it should be understoodthat a plurality of solder bumps, such as the solder bumps 103 of FIGS.1 a-1 c, may be formed above both pluralities of bond pads 204 and 205,and which for clarity are not shown. Furthermore, it should also beunderstood that the semiconductor chip 200 may be assembled in a chippackage using a flip-chip operation, much as described above withrespect to the semiconductor chip 102 of the chip package 100 andillustrated in FIGS. 1 a-1 b.

As shown in FIG. 2 a, the regularly shaped bond pads 204 may generallybe located in a substantially central region 203C of the semiconductorchip 200, and in certain illustrative embodiments may have a surfacearea that has a substantially regular geometric shape, as will bediscussed further with respect to FIGS. 2 b-2 c below. The irregularlyshaped bond pads 205, on the other hand, may in some illustrativeembodiments have a surface area that has a substantially irregulargeometric shape that is adapted to reduce the level of stresses and/orstrains induced in the metallization layers underlying the irregularlyshaped bond pads 205, as will also be discussed in additional detailwith respect to FIGS. 2 d-2 k below. Furthermore, the irregularly shapedbond pads 205 may be located at some distance away from the centralregion 203C, such as in each of the corner regions 200A-D of thesemiconductor chip 200, where chip package thermal interactions aretypically highest, and where white bump occurrence may be higher, aspreviously discussed. In certain illustrative embodiments, each of thecorner regions 200A-D may have a length 201C that is approximatelyone-tenth, or 10%, of the chip length 201, and a width 202C that isapproximately one-tenth, or 10%, of the chip width 202. Moreover, itshould be noted that in at least some illustrative embodiments of thepresent disclosure, both the plurality of regular bond pads 204 and theplurality of irregular bond pads 205 may be arranged on a substantiallysquare or rectangular grid-like pattern so as to facilitate thephotolithography patterning process that may be used to pattern thefinal metallization layer of the semiconductor chip, as well as thepassivation layer and the solder bumps formed thereabove. Moreover,depending on the device design and layout requirements, the spacingand/or density of the grid-like pattern may vary from area to area overthe semiconductor chip 200, or the grid-like pattern may continuesubstantially uninterrupted over the entirety of the semiconductor chip200.

FIG. 2 b schematically illustrates several different substantiallyregular geometric shapes that may be representative of the shape of thesurface area 204A of one or more of the plurality of regularly shapedbond pads 204. For purposes of the present disclosure, it should benoted that the term “substantially regular geometric shape” is notintended to be interpreted as a “regular polygon,” which would be ashape having a specific mathematical definition wherein the shape isboth equilateral (i.e., having equal length sides) and equiangular(i.e., having equally sized included angles). Instead, the term“substantially regular geometric shape” should be understood as beingdescriptive of a readily recognizable polygon or other geometric shape,such as a square, a rectangle, or an octagon, and the like, which may beformed using typical semiconductor manufacturing techniques. However, itshould be noted that a “substantially regular geometric shape” may notbe a precise “regular polygon” as described above, or have the exactgeometric accuracy as if such structures were drawn on paper withmathematical precision.

As shown in FIG. 2 b, the surface area 204A of any one of the regularlyshaped bond pads 204 may be any one of several substantially regulargeometric shapes, such as, for example: a) a square; b) a rectangle; c)an octagon; d) a circle; etc. Other substantially regular geometricshapes may also be used. Furthermore, in at least some embodiments, theregularly shaped bond pad 204 may be positioned so that a centroid 204Cof the surface area 204A may be located above a contact via 214 formedin the metallization layer underlying the bond pad 204. Additionally, asshown in FIG. 2 b, the contact via 214 may have a cross section(indicated as a dotted line) that is also one of several substantiallyregular geometric shapes, such as a square, rectangle, circle and thelike. Some specific aspects of a regularly shaped bond pad 204 having,for illustrative purposes only, a substantially square shape, areillustrated in FIG. 2 c and will now be discussed in further detail.

As shown in FIG. 2 c, the illustrative regularly shaped bond pad 204having a substantially square shape has surface area 204A and a surfacearea centroid 204C. Furthermore, it should be appreciated by one ofordinary skill in the art that any out-of-plane loads imposed on theregularly shaped bond pad 204 by the differential thermal interactionbetween the semiconductor chip 200 and a carrier substrate during thechip package assembly process, such as the loads 103T (tension), 103S(shear) and 103M (bending moment) shown in FIG. 1 c above, may beconsidered to act substantially along a vector 204V running from thecenter 203 of the chip 200 and the centroid 204C. Furthermore, the loadsimposed on the underlying metallization layers by the regularly shapedbond pad 204 will generally be proportional to the geometric propertiesof the surface area 204A of the bond pad 204 along the vector 204V.Accordingly, both the tension load (such as the tension load 103T; seeFIG. 1 c) and the shear load (such as the shear load 103S; see FIG. 1 c)imposed on the regularly shaped bond pad 204 during the chip packagethermal interaction will generally be distributed to the underlyingmetallization layers based on the surface area 204A of the regularlyshaped bond pad 204. On the other hand, the bending moment (such as thebending moment 103M; see FIG. 1 c) will generally be distributed to theunderlying metallization layers based on the length 204L of theregularly shaped bond pad 204 along the direction of the vector 204V.

With reference to FIGS. 2 d-2 e, in contrast to the geometric propertiesof the surface area 204A of the regularly shaped bond pad 204, thegeometric properties of the surface area 205A of the irregularly shapedbond pads 205 may be configured so as to reduce the magnitude of theloads imparted on the underlying metallization layers, thereby alsoreducing the likelihood of crack-like defects below the bond pads205—i.e., white bumps. For purposes of the present disclosure, it shouldbe noted that an irregularly shaped bond pad 205 is one that has asurface area 205A, which, when viewed from above and taken in itsentirety, does not have a “substantially regular geometric shape” aspreviously described with respect to the regularly shaped bond pads 204.Instead, the surface area 205A of the irregularly shaped bond pads 205may be representative of a more complex and irregular or compositegeometric shape. Unlike the “substantially regular geometric shapes” ofthe regularly shaped bond pads 204, it should be understood that an“irregular geometric shape” is one that is not a readily recognizablepolygon or other geometric shape, such as a square, a rectangle, or anoctagon, and the like.

In certain embodiments, the surface area 205A of the irregularly shapedbond pads 205 may be defined by a plurality of different contiguoussurface area portions when viewed from above. For example, as shown inFIG. 2 d, one illustrative irregularly shaped bond pad 205 defined bythe presently disclosed subject matter may have a surface area 205A thatis represented by a first portion 206 having a first portion surfacearea 206A and a second portion 207 having a second portion surface area207A. Stated another way, the surface area 205A is a composite surfacearea of the first portion surface area 206A and the second portionsurface area 207A. In some embodiments, the first portion surface area206A may be defined by a substantially regular geometric shape, such asa geometric shape that is substantially similar to that of the surfacearea 204A of the regularly shaped bond pads 204. On the other hand, thesecond portion surface are 207A may be representative of an irregulargeometric shape—i.e., a shape that is not a readily recognizablepolygon, square, or other geometric shape—as depicted in FIG. 2 d. Inother illustrative embodiments, both of the surface areas 206A and 207Amay represent irregular geometric shapes when viewed from above. Instill further embodiments, both of the surface areas 206A and 207A mayrepresent substantially regular geometric shapes, while the overallshape of the combined surfaces 206A, 207A, when viewed from above, isnot a readily recognizable geometric shape, such as a rectangle or asquare.

As shown in FIG. 2 d and noted above, the overall surface area 205A ofthe irregularly shaped bond pad 205 is a substantially contiguous shapewhich, for convenience of description, can be separated into a firstportion surface area 206A having a substantially regular geometricshape, i.e., a square, and a second portion surface area 207A having anirregular geometric shape. Accordingly, it should be understood thatwhen the surface area 205A is viewed from above it is a composite of thefirst and second portion surface areas 206A and 207A, wherein the firstportion surface area 206A is proximate or adjacent to the second portionsurface area 207A. Furthermore, it should also be understood that thesides 227A and 227B of the second portion surface area 207A may besubstantially aligned and flush with the sides 226A and 227B,respectively, of the first portion surface area 206A.

Some specific aspects of an irregularly shaped bond pad 205 having theirregular geometric shape as shown in FIG. 2 d are illustrated infurther detail in FIG. 2 e and described below.

As shown in FIG. 2 e, the illustrative irregularly shaped bond pad 205has an overall combined surface area 205A and a surface area centroid205C. Furthermore, the irregularly shaped bond pad 205 may be formedabove a contact via 215 (indicated in FIG. 2 e as a dotted line). Asnoted above with reference to FIG. 2 d, the irregularly shaped bond pad205 of FIG. 2 e can be broken down into a first portion surface area206A and a second portion surface area 207A. In certain embodiments, thefirst portion surface area 206A may be defined by a substantiallyregular geometric shape, such as the substantially square shapeillustrated in FIG. 2 e, while in other embodiments, differentsubstantially regular geometric shapes may also be used, e.g., asubstantially rectangular or octagonal shape, and the like.

As noted with respect to the regularly shaped bond pads 204 of FIG. 2 cabove, the loads imposed on the underlying metallization layers by theirregularly shaped bond pad 205 of FIG. 2 e may be similarlyproportional to the geometric properties of the overall combined surfacearea 205A of the irregularly shaped bond pad 205 along a vector 205Vrunning from the center 203 of the semiconductor chip 200 and throughthe centroid 205C. That is, both the tension load (such as the tensionload 103T) and the shear load (such as the shear load 103S) imposed onthe irregularly shaped bond pad 205 will generally be distributed to theunderlying metallization layers based on the overall combined surfacearea 205A of the irregularly shaped bond pad 205. Furthermore, thebending moment (such as the bending 103M) will generally be distributedto the underlying metallization layers based on a length 205L of theirregularly shaped bond pad 205 along the direction of the vector 205V.Accordingly, in those illustrative embodiments of the present disclosurewhere the first portion 206 of the irregular bond pad 205 has a surfacearea 206A that is substantially the same size and shape as the surfacearea 204A of the regularly shaped bond pad 204, an irregularly shapedbond pad 205 that also includes a contiguous second portion 207positioned substantially along the vector 205V will have a length 205Lthat is greater than the length 204L and an overall combined surfacearea 205A that is greater than the area 204A. As a result, the loadsimparted on any given point of the underlying metallization layers—andthe resultant stresses and strains—by the irregularly shaped bond pad205 may be displaced from sensitive underlying circuitry, and may belower than those on a similarly situated but regularly shaped bond pad204, thereby possibly reducing the likelihood of white bump occurrences.

The bond pads 204 and 205 illustrated in FIGS. 2 c and 2 e,respectively, may be formed in accordance with substantially similarprocessing steps. For example, a last metallization layer, such as themetallization layer 104A shown in FIG. 1 c, may be formed above ametallization layer comprising a low-k or ULK material, such as themetallization layer 104B of FIG. 1 c. The last metallization layer mayformed of a typical dielectric material having a higher materialstrength than the low-k or ULK material of the underlying layer, such assilicon dioxide, silicon nitride, and the like. Next, the lastmetallization layer is patterned to form a bond pad opening above, forexample, a contact via formed in the underlying low-k/ULK metallizationlayer using photolithography techniques well known in the art. Dependingon the location of the specific bond pad—i.e., the central region 203Cor the corner regions 200A-D—the shape of the patterned bond padopenings formed in the last metallization layer may substantiallyconform to that of either the regularly shaped bond pad 204 (in thecentral region 203C) or of the irregularly shaped bond pad 205 (in thecorner regions 200A-D). Thereafter, a deposition process is performed,such as an electrochemical deposition process and the like, to form alayer of conductive metal in the bond pad openings and above the lastmetallization layer. Depending on the device and/or process flowrequirements, the conductive metal may be copper, aluminum, or alloysthereof. Finally, a planarization process is performed to remove excessmaterial of the layer of conductive metal from above the lastmetallization layer.

As noted previously, both the regularly shaped bond pads 204 and theirregularly shaped bond pads 205 may be formed on a substantially squareor rectangular grid-like pattern. Additionally, in those embodiments ofthe presently disclosed subject matter where the shape and size of theregularly shaped bond pads 204 is substantially the same as that of thefirst portion 206 of the irregularly shaped bond pads 205 (asillustrated in FIGS. 2 c and 2 e), only minor adjustments may benecessary to the pattern used to form the openings for the irregularlyshaped bond pads 205 in the corner areas 200A-D as compared to theopenings for the regularly shaped bond pads 204 in the central region203C. Accordingly, in at least some integration schemes, there may beonly a negligible impact on the overall device processing flowrequirements.

Also as noted previously, the thermal interaction between thesemiconductor chip 200 and a carrier substrate cause by the CTE mismatchduring the chip packaging process is proportionally greater in thoseareas of the chip 200 that are at the greatest distance from the center203 of the chip 200 i.e., the corner regions 200A-D. Accordingly, thegreatest benefit in reducing the likelihood of white bump defects mayaccrue to those embodiments where the second portion 207 of theirregular bond pad 205 is positioned substantially along the vector 205Vas shown in FIG. 2 e and at a greater distance from the center 203 ofthe semiconductor chip 200 than the first portion 206. FIG. 2 f, whichschematically illustrates the geometric relationship of the first andsecond portions 206, 207 of the irregularly shaped bond pad 205, willnow be described.

As shown in FIG. 2 f, the first portion 206 has a first portion surfacearea 206A and a surface area centroid 206C, and the second portion 207has a second portion surface area 207A and a surface area centroid 207C.The centroid 206C is located at a distance 206R from the center 203 ofthe semiconductor chip 200, and the centroid 207C is located at distance207R from the center 203 that is greater than the distance 206R.Furthermore, in at least some embodiments, the irregularly shaped bondpad 205 may be positioned on the semiconductor chip 200 such that thecentroid 206C of the first portion surface area 206A may be locatedabove the contact via 215 (indicated by a dotted line).

Additionally, in certain illustrative embodiments, when viewed fromabove, no portion of the surface area 206A extends beyond a distance206Y from the centerline 203X of the semiconductor chip 200, whereas atleast a portion of the surface area 207A may be located at distance 207Yfrom the centerline 203X that is greater than the distance 206Y.Similarly, in other embodiments, no portion of the surface area 206Aextends beyond a distance 206X from the centerline 203Y, whereas atleast a portion of the surface area 207A may be located at distance 207Xfrom the centerline 203Y that is greater than the distance 206X.

FIGS. 2 g-2 k schematically depict other illustrative irregularly shapedbond pads 205 of the present disclosure, where the first portion 206 isdefined by a substantially regular geometric shape and the secondportion 207 is defined by at least a part of a substantially regulargeometric shape. For example, FIGS. 2 g-2 k each illustrate anirregularly shaped bond pad 205 that includes a first portion 206 thatis a substantially square shape, whereas the second portion 207 in eachof the FIGS. 2 g-2 k is a part of a different substantially regulargeometric shape. In FIG. 2 g, for example, the second portion 207 is apart of substantially circular shape, whereas in FIGS. 2 h-2 k thesecond portion 207 is a part of a substantially triangular shape, asubstantially square shape, a substantially hexagonal shape, and asubstantially octagonal shape, respectively. Other substantially regulargeometric shapes may be used for the second portion 207, or anyirregular geometric shape may also be used. Additionally, it should benoted that as previously described, in other illustrative embodiments,the first portion 206 shown in FIGS. 2 g-2 k may also be anysubstantially regular geometric shape other than a square, or it mayalso be an irregular geometric shape.

FIG. 2 l schematically depicts a further illustrative irregularly shapedbond pad 205 in accordance with the present disclosure, where the firstportion 206 is a substantially square shape, but where the secondportion 207 may be made up of a plurality of sub-portions, such as thesub-portions 207-1, 207-2 and 207-3. Furthermore, in at least someembodiments, each of the plurality of sub-portions 207-1, 207-2 and207-3 may also be at least a part of substantially regular geometricshape. For example, in the illustrative embodiment shown in FIG. 2 l,each of the sub-portions 207-1, 207-2 and 207-3 may be a part of asubstantially rectangular shape, whereas in other embodiments, each ofthe sub-portions 207-1, 207-2 and 207-3 may be a part of different typeof substantially regular geometric shapes.

FIG. 2 m schematically illustrates yet a further illustrativeirregularly shaped bond pad 205, where the first portion is asubstantially square shape, but where the second portion 207 may be acomposite shape having two or more sub-parts, such sub-parts 207-1 and207-2. Furthermore, one or more of the subparts 207-1 and 207-2 may alsobe at least a part of substantially regular geometric shape, aspreviously described. For example, in the embodiment depicted in FIG. 2m, the first sub-part 207-1 is a part of a substantially octagonalshape, whereas the second sub-part 207-2 of the composite shape 207 is asubstantially square shape. Other substantially regular geometric andirregular geometric shapes may also be used.

FIGS. 3 a-3 f, which schematically depict additional illustrative bondpad structures of the present disclosure, will now be described.

FIG. 3 a schematically depicts a bond pad 304 of a representativesemiconductor chip, where the bond pad 304 has a typical bond padconfiguration that is substantially similar to the regularly shaped bondpad 204 shown in FIG. 2 c and described above. As with the regularlyshaped bond pad 204, the surface area 304A of the bond pad 304 may havea substantially regular geometric shape, wherein in the illustrativeembodiment shown in FIG. 3 a, the surface area 304A may be asubstantially rectangular shape having a length 304L and a width 304W.Depending on the overall device design and the bond pad layout of thesemiconductor chip, the length 304L and width 304W may range in size upto 200μ, whereas in specific applications, the length 304L and width304W may be on the order of 40-50μ. Furthermore, the bond pad 304 has anupper surface 304S as shown in Section A-A of FIG. 3 a, and the surfacearea 304A has a surface area centroid 304C.

FIG. 3 b schematically depicts one illustrative embodiment of acomposite bond pad 305 according to the present disclosure that is madeup of a base bond pad portion 306 and a strain-buffering bond padportion 307 above the base bond pad portion 306, such that the compositebond pad 305 has a substantially non-planar upper surface 305S. Incertain illustrative embodiments, the strain-buffering bond pad portion307 may be positioned along two sides 325A, 325B of the composite bondpad 305, and is generally configured to reduce the amount of strainenergy that is transmitted through the composite bond pad 305 and intoany underlying metallization layers as a result of the CTE mismatch andconsequent thermal interaction during the chip packaging process, aspreviously described.

As shown in FIG. 3 b, in some illustrative embodiments the base bond padportion 306 may be substantially similar in size and shape to the bondpad 304 illustrated in FIG. 3 a and described above—that is, where thebase bond pad portion 306 has a surface area 306A representing asubstantially regular geometric shape (e.g., a substantially rectangularshape), an upper surface 306S, a surface area centroid 306C, a length306L and a width 306W. The strain-buffering bond pad portion 307 ispositioned above the upper surface 306S of the base bond pad portion306, and has a surface area 307A that may represent an irregulargeometric shape, and an upper surface 307S that is located above theupper surface 306S of the base bond pad portion 306. Furthermore, thesurface area 307A of the strain-buffering bond pad portion 307 also hasa surface area centroid 307C.

In some illustrative embodiments, the strain-buffering bond pad portion307 may be a part of a substantially regular geometric shape, such as,for example, a substantially rectangular shape (indicated by the dottedlines in FIG. 3 b) having a length 307L and a width 307W. Furthermore,the strain-buffering bond pad portion 307 may be made up of a first part307-1 along the length 327L and a second part 307-2 along the width307W, as shown in FIG. 3 b. Additionally, in at least some embodiments,the first part 307-1 may have a thickness 328 and the second part 307-2may have a thickness 329. Depending on the overall design of thecomposite bond pad 305, the thickness 328 may be, in certainembodiments, approximately 5-10% of the length 307L, whereas in otherillustrative embodiments the thickness 329 may be approximately 5-10% ofthe width 307W. For example, thicknesses 328, 329 may range betweenapproximately 2-10μ, depending on the overall size and configuration ofthe composite bond pad 305. Other thicknesses 328, 329 of the first andsecond parts 307-1, 307-2, both larger and smaller, may also be used.

In certain illustrative embodiments of the subject matter disclosedherein, the strain-buffering bond pad portion 307 may be positionedabove the base bond pad portion 306 such that a side 327A of the firstpart 307-1 of portion 307 may be proximate to a side 326A of portion306. Furthermore, in at least some embodiments, the side 327A may bealigned substantially parallel to and substantially flush with the side326A as shown in FIG. 3 b, whereas in other illustrative embodiments,the side 327A may be aligned substantially parallel to the side 326A butoffset from the side 326A by a distance 330, as shown in FIG. 3 c.Depending on the device design requirements, the offset distance 330 mayrange from approximately 5-10% of the length 307L, and in certainembodiments may be approximately 2-10μ. Other offset distances 330, bothlarger and smaller, may also be used.

Similarly, in other illustrative embodiments, a side 327B of the secondpart 307-2 may also be proximate to a side 326B of the base bond padportion 306. Furthermore, as with the side 327A, in certain embodimentsthe side 327B may be aligned substantially parallel to and substantiallyflush with the side 326B as shown in FIG. 3 b, whereas in otherillustrative embodiments, the side 327B may be aligned substantiallyparallel to the side 326B but offset from the side 326B by a distance331, as shown in FIG. 3 c. The offset distance 331 may range fromapproximately 5-10% of the length 307L, and in certain embodiments maybe approximately 2-10μ. Other offset distances 331 may also be used.

In some embodiments, the length 307L may be substantially the same asthe length 306L (as illustrated in FIG. 3 b), whereas in otherembodiments the length 307L may be different than the length 306L.Similarly, in certain embodiments the width 307W may be substantiallythe same as the width 306W (as illustrated in FIG. 3 b), whereas inother embodiments the width 307W may be different than the width 306W.For example, FIG. 3 d schematically shows illustrative composite bondpads 305 where the sides 327A and 327B of the strain-buffering bond padportion 307 are aligned substantially parallel to and substantiallyflush with the sides 326A and 326B of the base bond pad portion 306,with various relationships between the lengths 307L/306L and the widths307W/306W. Similarly, FIG. 3 e schematically depicts illustrativecomposite bond pads 305 where the sides 327A and 327B of thestrain-buffering bond pad portion 307 are aligned substantially parallelto but offset from the sides 326A and 326B of the base bond pad portion306, showing various relationships between the lengths 307L/306L and thewidths 307W/306W. It should be noted, however, that the above disclosureand the associated Figures should not be construed to limit in any wayeither of the relative lengths 306L and 307L, or either of the relativewidths 306W and 307W, as other relative combinations of lengths andwidths may also be used.

As noted with respect to FIGS. 2 a-2 m above, the thermal interactionbetween a semiconductor chip and a carrier substrate cause by the CTEmismatch during the chip packaging process is proportionally greater inthose areas of a semiconductor chip that are at the greatest distancefrom the center of the chip, such as, for example, in the corner regions200A-D of the semiconductor chip 200 illustrated in FIG. 2 a.Accordingly, it should be understood that the greatest benefit inreducing the likelihood of white bump defects may accrue to thoseembodiments of the present disclosure where the additional materialstrain-buffering bond pad portion 307 of the composite bond pad 305 ispositioned above the base bond pad portion 306 but as far away aspossible from the center of a semiconductor chip (not shown) on whichthe composite bond pad 305 is formed. FIG. 3 f, which schematicallyillustrates the geometric relationship between the base bond pad portion306 and the strain-buffering bond pad portion 307 of the composite bondpad 305 shown in FIG. 3 b, will now be described.

FIG. 3 f illustrates the strain-buffering bond pad portion 307positioned along a vector 305V running between a center 303 of asemiconductor chip (not shown) on which the composite bond pad 305 isformed (such as the semiconductor chip 200 illustrated in FIG. 2 a anddescribed above) and the composite bond pad 305. As shown in FIG. 3 f,in one illustrative embodiment, the strain-buffering bond pad portion307 may generally be positioned proximate to the sides of the compositebond pad 305 that are farthest away from the center 303 along thedirection of the vector 305V. Additionally, in at least some embodimentsdisclosed herein, the composite bond pad 305 may be positioned on thesemiconductor chip (not shown) above a contact via 315 (indicated inFIG. 3 f by a dotted line), whereas in certain embodiments, the centroid306C of the surface area 306A of the base bond pad portion 306 may belocated above the contact via 315. Furthermore, the centroid 306C islocated at a distance 306R from the center 303, and the centroid 307C ofthe surface area 307A of the strain-buffering bond pad portion 307 islocated at distance 307R from the center 303 that is greater than thedistance 306R.

Additionally, in certain illustrative embodiments, the centroid 306C maybe located at a distance 306Y from a centerline 303X of thesemiconductor chip (not shown), whereas the centroid 307C may be locatedat distance 307Y from the centerline 303X that is greater than thedistance 306Y. In other embodiments, the centroid 306C may be located ata distance 306X from a centerline 303Y of the semiconductor chip (notshown), whereas the centroid 307C may be located at distance 307X fromthe centerline 303Y that is greater than the distance 306X.

FIGS. 3 g-3 h schematically illustrate additional illustrative compositebond pads 305 according to the present disclosure.

FIG. 3 g schematically shows an illustrative composite bond pad 335 thatis substantially similar to the composite bond pad 305 of FIGS. 3 b and3 f, wherein however the composite bond pad 335 of FIG. 3 g furtherincludes a second strain-buffering bond pad portion 308 positioned abovethe base bond pad portion 306. The second strain-buffering bond padportion 308 has a surface area 308A and a surface area centroid 308C, aswell as an upper surface 308S that is above the upper surface 306S ofthe base bond pad portion 306. The centroid 308C is located at adistance 308R from a center 303 of a semiconductor chip (not shown) onwhich the composite bond pad 335 is formed that is less than thedistance 307R from the center 303 to the centroid 307 of thestrain-buffering bond pad portion 307. Furthermore, in certainillustrative embodiments, the upper surface 308S may be substantiallyco-planar with the upper surface 307S of the strain-buffering bond padportion 307, whereas in other embodiments, the upper surface 308S may beeither higher or lower than the upper surface 307S, relative to theupper surface 306S.

In certain embodiments of the present disclosure, the secondstrain-buffering bond pad portion 308 may have a thickness 338 along alength 306L of the base bond pad portion 306, and may also have athickness 339 along a width 306W. Additionally, the secondstrain-buffering bond pad portion 308 may be offset from thestrain-buffering bond pad portion 307 such that the portion 308 is notin physical contact with the portion 307, as shown in FIG. 3 g. Forexample, the second strain-buffering bond pad portion 308 may be offsetfrom the strain-buffering bond pad portion 307 by a distance 340 alongthe length 306L and by a distance 341 along the width 306W. Furthermore,in some illustrative embodiments the thicknesses 338, 339 and the offsetdistances 340, 341 may range from approximately 5-10% of the respectivelength 306L or width 306W, as may be appropriate, and in certainembodiments may be approximately 2-10μ. Other thicknesses and offsetdistances may also be used.

FIG. 3 h schematically illustrates yet another illustrative compositebond pad 345 that is substantially similar to the composite bond pad 305of FIG. 3 g above, wherein however the bond pad 345 further includes athird strain-buffering bond pad portion 309 positioned above the basebond pad portion 306. The third strain-buffering bond pad portion 309has a surface area 309A and a surface area centroid 309C, as well as anupper surface 309S that is above the upper surface 306S of the base bondpad portion 306. The centroid 309C is located at a distance 309R from acenter 303 of a semiconductor chip (not shown) on which the compositebond pad 345 is formed that is less than either of the distances 307Rand 308R. Furthermore, in certain illustrative embodiments, the uppersurface 309S may be substantially co-planar with either or both of theupper surfaces 307S and 308S of the strain-buffering bond pad portion307 and the second strain-buffering bond pad portion 308, respectively,whereas in other embodiments, the upper surface 309S may be eitherhigher or lower than one or both of the upper surfaces 307S and 308S,relative to the upper surface 306S.

Similar to the second strain-buffering bond pad portion 308 describedabove, in certain embodiments the third strain-buffering bond padportion 309 may have a thickness 348 along the length 306L, and may alsohave a thickness 349 along the width 306W. The third strain-bufferingbond pad portion 309 may also be offset from the second strain-bufferingbond pad portion 308 such that the portion 309 is not in physicalcontact with the portion 308, as shown in FIG. 3 h. In at least someillustrative embodiments, the third strain-buffering bond pad portion309 may be offset from the second strain-buffering bond pad portion 308by a distance 350 along the length 306L and by a distance 351 along thewidth 306W. Additionally, in certain illustrative embodiments thethicknesses 348, 349 and the offset distances 350, 351 may range fromapproximately 5-10% of the respective length 307L or width 306L, as maybe appropriate, and at least one embodiment may be approximately 2-10μ.Other thicknesses and offset distances may also be used.

The composite bond pads 305, 335, and 345 illustrated in FIGS. 3 b-3 f,3 g, and 3 h respectively, may be formed in accordance withsubstantially similar processing steps. For example, the base bond padportions 306 may be formed substantially as described with respect tothe bond pads 204 and 205 described above. After planarizing the surfaceof the base bond pad portions 306, a sacrificial material layer may beformed above the last metallization layer, and a subsequent patterningprocess may be performed so as to define the openings forstrain-buffering bond pad portions 307, 308, 309. Thereafter, a furtherdeposition process, such as an electrochemical deposition process andthe like, may be performed so as to deposit a second layer of conductivemetal in the openings for the strain-buffering bond pad portions 307,308, 309 and above the sacrificial layer. The second layer of conductivemetal may be any one of several conductive metals that is bondable tothe conductive metal of the base bond pad portions 306, such as copper,aluminum, and alloys thereof. A further planarization process may thenbe performed to remove the excess portions of the second layer ofconductive metal from above the sacrificial material layer. Finally thesacrificial material layer is removed by a suitable etch process that isselective relative to the materials of the upper metallization layer,the base bond pad portion 306, and the strain-inducing bond pad portions307, 308, 309.

As a result, the subject matter disclosed herein provides bond padconfigurations that control, or at least mitigate, the effects ofsemiconductor chip and carrier substrate interactions during the chippackaging process, thereby reducing the likelihood of white bumpoccurrences.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. For example, the process steps set forth above may beperformed in a different order. Furthermore, no limitations are intendedto the details of construction or design herein shown, other than asdescribed in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Accordingly, the protection sought herein is as set forth inthe claims below.

What is claimed:
 1. A semiconductor chip, comprising: at least oneintegrated circuit device; and a bond pad that is electrically connectedto said at least one integrated circuit device, said bond pad having anirregular overall configuration when viewed from above that correspondsto a first area portion that is defined by a first substantially regulargeometric shape when viewed from above and a second area portionadjacent to said first area portion, wherein at least a part of saidsecond area portion is located at a greater distance from a centerlineof said semiconductor chip than any part of said first area portion whenviewed from above, and wherein two sides of said first area portion aresubstantially aligned with and substantially flush with two respectivesides of said second area portion.
 2. The semiconductor chip of claim 1,wherein said second area portion is defined by at least a part of asecond substantially regular geometric shape when viewed from above. 3.The semiconductor chip of claim 2, wherein said irregular overallconfiguration further corresponds to a third area portion adjacent tosaid first area portion, said third area portion is defined by at leasta part of a third substantially regular geometric shape when viewed fromabove, and at least a part of said third area portion when viewed fromabove is located at a greater distance from said centerline than anypart of said first area portion when viewed from above.
 4. Thesemiconductor chip of claim 1, wherein said bond pad is locatedproximate to a corner of said semiconductor chip.
 5. The semiconductorchip of claim 4, wherein said semiconductor chip has a length and awidth, and said bond pad is located within a first distance from saidcorner along said length that is approximately 10% of said length andwithin a second distance from said corner along said width that isapproximately 10% of said width.
 6. The semiconductor chip of claim 1,wherein said first substantially regular geometric shape issubstantially rectangular.
 7. The semiconductor chip of claim 2, whereinsaid second substantially regular geometric shape is substantiallyoctagonal.
 8. The semiconductor chip of claim 2, wherein said secondgeometric shape is substantially rectangular.
 9. The semiconductor chipof claim 1, wherein said bond pad is in a last metallization layer of ametallization system that comprises at least one metallization layercomprising a low-k dielectric material having a dielectric constant ofapproximately 3.0 or lower.
 10. The semiconductor chip of claim 1,wherein said bond pad is in electrical contact with a contact via in ametallization layer below said bond pad, and a centroid of said firstsubstantially regular geometric shape is positioned over said contactvia.
 11. The semiconductor chip of claim 1, further comprising a secondbond pad having a configuration that corresponds to a substantiallyregular geometric shape that is substantially the same as said firstsubstantially regular geometric shape, wherein said second bond pad iscloser to said centerline than said bond pad.
 12. The semiconductor chipof claim 1, further comprising a solder bump positioned above andelectrically contacting said bond pad.
 13. The semiconductor chip ofclaim 1, wherein an upper surface of said first area portion issubstantially coplanar with an upper surface of said second areaportion.
 14. A semiconductor chip, comprising: at least one integratedcircuit device; and a bond pad that is electrically connected to said atleast one integrated circuit device, said bond pad having asubstantially irregularly shaped overall bond pad configuration whenviewed from above that comprises: a first bond pad area portion that isdefined by a first substantially regular geometric shape when viewedfrom above; and a second bond pad area portion that is defined by atleast part of a second substantially regular geometric shape when viewedfrom above, wherein an upper surface of said second bond pad areaportion is substantially coplanar with an upper surface of said firstbond pad area portion and two sides of said first bond pad area portionare substantially aligned with and substantially flush with tworespective sides of said second bond pad area portion.
 15. Thesemiconductor chip of claim 14, wherein said substantially irregularlyshaped overall bond pad configuration further comprises a third bond padarea portion that is defined by at least a part of a third substantiallyregular geometric shape when viewed from above.
 16. The semiconductorchip of claim 15, wherein at least one side of said third bond pad areaportion is substantially aligned with and substantially flush with arespective side of said first bond pad area portion.
 17. Thesemiconductor chip of claim 15, wherein at least one side of said thirdbond pad area portion is substantially aligned with and substantiallyflush with a respective side of said second bond pad area portion. 18.The semiconductor chip of claim 14, wherein said bond pad is locatedproximate to a corner of said semiconductor chip.
 19. The semiconductorchip of claim 18, wherein said semiconductor chip has a length and awidth, and said bond pad is located within a first distance from saidcorner along said length that is approximately 10% of said length andwithin a second distance from said corner along said width that isapproximately 10% of said width.
 20. The semiconductor chip of claim 12,wherein said bond pad is in a last metallization layer of ametallization system comprising at least one metallization layer thatcomprises a low-k dielectric material having a dielectric constant ofapproximately 3.0 or lower.
 21. A semiconductor chip, comprising: afirst integrated circuit device; a second integrated circuit device; afirst bond pad that is electrically connected to said first integratedcircuit device, said first bond pad having a substantially irregularlyshaped overall bond pad configuration when viewed from above thatcomprises: a first bond pad area portion that is defined by a firstsubstantially regular geometric shape when viewed from above, said firstbond pad area portion having a first area centroid that is located at afirst distance from a center of said semiconductor chip; and a secondbond pad area portion that is defined by at least part of a secondsubstantially regular geometric shape when viewed from above, saidsecond bond pad area portion having a second area centroid that islocated at a second distance from said center of said semiconductor chipthat is greater that said first distance; and a second bond pad that iselectrically connected to said second integrated circuit device, saidsecond bond pad having a substantially regularly shaped overall bond padconfiguration when viewed from above that is defined by a thirdsubstantially regular geometric shape that is substantially the same assaid first substantially regular geometric shape, said thirdsubstantially regular geometric shape having a third area centroid thatis located a third distance from said center of said semiconductor chipthat is less than said first distance.
 22. The semiconductor chip ofclaim 21, wherein two sides of said first bond pad area portion aresubstantially aligned with and substantially flush with two respectivesides of said second bond pad area portion, and wherein an upper surfaceof said first bond pad area portion is substantially coplanar with anupper surface of said second bond pad area portion.
 23. Thesemiconductor chip of claim 21, further comprising a first solder bumppositioned above and electrically contacting said first bond pad and asecond solder bump positioned above and electrically contacting saidsecond bond pad.